This page presents a dedicated software that computes reliable seeing from star image. This is a "doubled star" created by adding a two holes mask and wedge prism at the telescope entrance pupil. It produces accurate results to measure the atmospheric turbulence from the ground to the outer atmosphere.

This software has being used to characterize the Extremly Large Telescope (ELT) seeing at potential sites in Morroco.

Many prestigious institute, and some that are not related to Astronomy, are using our software for turbulence measurements.

Any directshow camera can work with the software.
ALCOR-SYSTEM can sell validated cameras for your project. Resolution, can be from 1200x960 to 1900x1200 pixels with 30 to 60 frames per second. Computer interface can be USB or Ethernet.
Contact us for getting suitable cameras.

Cameras not able to provide directshow stream such as SBIG camera, or any slow readout image to image CCD camera is not compliant to our software.
If you have already a camera ask us to know wether your camera is suitable to our software, or try your camera withe the evaluation version of the software.
DIMM "Manual Mode" software
The ESO DIMM Monitor (M.Sarazin, F.Roddier)  PDF
Measuring Astronomical seeing: the DA/IAC DIMM (J.Vernin,C Muñoz-Tuñon) PDF
Wavefront outer scale and seeing measurements at San Pedro Martir Observatory (R.Conan, R.Avila and all). PDF
A digital video camera can be used to acquire the data, and thanks to their frame rate (up to 30 frames per second, depending on the model), it is possible to perform a real time analysis and compute the seeing based on the method explained hereafter :
Software screen shots
ALCOR-SYSTEM has two software available to provide the atmospheric seeing figure :
- a fully automatic software that performs seeing measurements from dusk till dawn. No user attendance is required.
- a manual software, that performs the same measurements but the telescope needs to be attended by a user to change star to another. Nevertheless autoguiding is provided. This page presents this software.

The software is available for 30 days trial, with no functionnality limitations. it runs under WINDOWS 7,8 and 10
To order the software please contact us.
The software manual is available in this link :
Tests and validation
Main software control tab
Results tab
Star measurement selection
Thanks to the ASCOM interface, the telescope can be slewed to the target, and autoguiding performed if the "PulseGuide" command is available in the mount ASCOM interface.
Autoguiding calibration procedure
The next video shows the system in operation with a 180 mm diameter telescope :
With a two hole mask, aperture of the hole shall be 50 mm at least and hole to hole distance center of 150mm.

The next three plot have been recorded in July 2008, (X axis = Julian date) , this is the computed seeing with Altair and computed as if it would be zenithal seeing.
The next plot is again Altair, three days after, the seeing is worse compared to the previous night.
A combined test has been achieved : Brice Oliver Demory and Marc Sarazin had compared the standard ESO DIMM and the seeing measurements provided by this software with another telescope, at the same time and place.

The place was ESO la Silla Observatory. Themobile telescope apparatus and the software presented in this page, and the official ESO DIMM where located 100m appart. The black dashed line is the ALCOR-SYSTEM softwaren and the red is the official ESO DIMM at la Silla Obs.
Here is a seeing measurment with Capella star, using an Intes 180mm (two 50 mm holes separated by 125mm center to center).
It turned out that the two systems (different in telescope, camera and software) output the same data !

This is a good indicator : the two different systems outputs the same results.